Keywords: Kenaf fiber; radiation; electron beam; graft polymerization; mechanical properties

Abstract

This paper focuses on the effect of absorbed radiation dose by electron beam on the mechanical properties of untreated and pre-treated kenaf fibers with sodium chlorite (NaClO₂), which were subsequently grafted with glycidyl methacrylate (GMA). Changes to properties of the fibers after graft polymerization process were analysed via Fourier transform infra-red spectroscopy (FTIR) analysis. The morphological changes were observed by field emission scanning electron microscopy (FESEM). The results indicated that untreated kenaf fibers showed superior mechanical properties compared to treated kenaf fibers. This was mainly due to deterioration in lignin content as the concentration of NaClO₂ increased. Lignin is responsible for keeping microfibrils intact. Thus, the reduction in lignin content leads to alteration in the mechanical strength of fibers, as it causes bond cleavage between lignin and polysaccharide molecules. On the other hand, non-radiated kenaf fibers showed higher tensile strength and tensile modulus compared to radiated kenaf fibers for all doses. The tensile strength of non-radiated kenaf fibers was around 245.8 MPa, which reduced up to 224.3 MPa when subjected to irradiation of 10 kGy. However, the tensile strength of kenaf fibers irradiated at 100 kGy was recorded at 125.6 MPa. Grafted kenaf fibers exhibited moderate mechanical properties and significant changes were observed as the absorbed radiation dose increased. This research would provide the technical basis for preparation of radiation-induced grafted kenaf adsorbents with an overview on emphasizing a significant factor which affects the mechanical properties of kenaf fibers.